This invention relates to a miniature multiple electrical connector which is able to prevent deformation of a metal shell for shielding.
With miniaturization of electronic appliances, multiple connectors for use in connections between circuits have been required to be more miniaturized. Moreover, connectors have often been required to have very narrow widths, although long lengths are accepted, depending upon the amount of space available in electronic appliances in which the connectors are used. Therefore, thin type miniature multiple electrical connectors are not unusual which have a great number (for example, as many as 80) of contacts arranged in insulating blocks, for example, having a width of about 6 mm and a length of about 50 mm.
With a connector used in an electronic appliance, the following means has been provided in order to prevent malfunctioning of the appliance due to outward noise. As shown in FIGS. 6a and 6b illustrating a plug connector A, contacts 1 are arranged on the fitting protrusion 2a of an insulating block 2 having mounting flanges 2b at both its ends. A trapezoid metal shell 3 is formed with punched projections 3a arranged in rows on inner sides thereof for contacting (as later described) and has mounting flanges 3b at both its ends. The metal shell 3 is fixed on the insulating block 2 to surround the fitting protrusion 2a of the insulating block 2 with clearances therebetween.
On the other hand, as shown in FIGS. 6c and 6d illustrating a receptacle connector B mating with the plug connector A shown in FIGS. 6a and 6b, contacts 4 are arranged in two rows on the inside of the fitting recess 5a of an insulating block 5 having mounting flanges 5b. A trapezoid metal shell 6 having mounting flanges 6a at both its ends is fixed on the mounting flanges 5b of the insulating block 5 to surround the fitting recess 5a of the insulating block 5 so that the metal shell 6 is inserted in the metal shell 3 of the plug connector A to be in contact therewith through the punched projections 3a thereof. When the plug connector A is inserted into the receptacle connector B, the contacts 1 and 4 are brought into contact with each other and simultaneously the metal shells 3 and 6 are also brought into electrical contact with each other to be connected to an earth circuit. The conductive portions of the plug and receptacle connectors A and B are shielded in this manner.
In the prior art described above, however, upon inserting the plug connector A into the receptacle connector B, the metal shell 6 of the receptacle connector B is often deformed as shown by broken lines in FIG. 7, making the insertion impossible due to means for fixing the metal shell 6 to the insulating block 5 of the receptacle connector B as explained hereinafter.
As shown in FIGS. 6c and 6d and FIG. 7, the metal shell 6 is provided along its lower edges on both sides with a plurality of fixing tongues 6b, each extending downwardly and having an anchoring aperture 6c. In the embodiment shown in FIG. 6d, the fixing tongues 6b are provided at both the ends and at the center of the metal shell 6. On the other hand, the insulating block 5 is provided along both its sides with anchoring protrusions 5c adapted to be fitted in the anchoring apertures 6c of the fixing tongues 6b of the metal shell 6 so that the metal shell 6 is fixed to the insulating block 5.
With such fixing means, when the metal shell 6 is fitted onto the insulating block 5, the fixing tongues 6b ride over the anchoring protrusions 5c and then the anchoring protrusions 5c snap into the anchoring apertures 6c. The fixing means simplify the assembling of the receptacle connector B and make possible the thin construction of the receptacle connector B.
On the other hand, at the beginning of the insertion of the plug connector A into the receptacle connector B, particularly the fixing tongues 6b at the center, tend to disengage from the anchoring protrusions 5c to release the fixation therebetween and the metal shell 6 thereby becomes considerably deformed by further insertion of the plug connector A into the receptacle connector B.
As a result, even if the plug connector A can be forcedly removed from the receptacle connector B, the plug connector A can seldom be inserted thereinto again because of the deformation of the metal shell 6 which must then be replaced with a new one.